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Irreversible electroporation

Irreversible electroporation (IRE or NTIRE for non-thermal irreversible electroporation) is a soft tissue ablation technique using ultra short but strong electrical fields to create permanent and hence lethal nanopores in the cell membrane, to disrupt the cellular homeostasis.

The resulting cell death results from apoptosis and not necrosis as in all other thermal or radiation based ablation techniques.

The main use of IRE lies in tumor ablation in regions where precision and conservation of the extracellular matrix, blood flow and nerves are of importance. The technique is in an experimental stage and has not been approved for use outside of clinical trials.

Utilizing ultra short pulsed but very strong electrical fields, micropores and nanopores are induced in the phospholipid bilayers which form the outer cell membranes.

A number of electrodes, in form of long needles, are placed around the target volume. The point of penetration for the electrodes is chosen according to anatomical conditions. Imaging is essential to the placement and can be achieved by ultrasound, magnetic resonance imaging or tomography. The needles are then connected to the IRE-generator, which then proceeds to sequentially build up a potential difference between two electrodes. The geometry of the IRE-treatment field is calculated in real time and can be influenced by the user. Depending on treatment-field and number of electrodes used, the ablation takes between 1 to 10 minutes of time. In general muscle-relaxants are administered, since even under general anaesthetics, strong muscle-contractions are induced by excitation of the motor end-plate.

One specific device for the IRE procedure is the so-called The NanoKnife system manufactured by AngioDynamics which has received premarket notification from the FDA.

Scope of applications:

Prostate: Using IRE, the urethra, bladder, rectum and neurovascular bundle can potentially be included in the treatment field without taking (permanent) damage. This would potentially give IRE superiority both for focal therapy and whole gland treatments compared to all other available methods.

Liver, kidney, and pancreas: Several inoperable tumors of the liver and the kidney can be treated using IRE. This is due to tissue selectivity regarding blood vessels and epithelial type tissue.

Other organs: the feasibility of IRE for breast cancer and other heterogeneous tissue organs have been reported.